Calcification of blood contacting surfaces has been the key impediment to the development of polymeric cardiac valve prostheses and other polymeric implantables. The deposition of calcium plaques as hydroxyapatite rigidifies leaflets and potentially leads to valve dysfunction. That calcification proceeds preferentially along surfaces undergoing flexion stress only exacerbates the problem. The proposed work is based on the hypothesis that calcification along flexing polymeric surfaces arises from increased calcium permeability due to flexion stress/strain. Accordingly, modifications to the polymer surface which can inhibit calcium adsorption and permeation, and which are stable to cyclic flexion will reduce the calcification rate of implanted polymeric components. To test this hypothesis, the surfaces of polyetherurethane disks, trileaflet valves, and valved conduits will undergo modification by inert ion implantation and by ion beam assisted deposition of titanium and of sialon ceramic. These methodologies alter surface properties at the micron level, but leave bulk polymer attributes unaffected. In-vitro and in-vivo studies will be conducted to assess the degree to which calcification rate is reduced by ion beam based surface modification (IBSM) and to establish the most efficacious of the IBSM treatments for longer term implantation. PROPOSED COMMERCIAL APPLICATION: The potential application will be to the more than 100,000 people worldwide who receive hart valve replacement. The proposed work would lead to development of a polyurethane valve prosthesis with reduced calcification susceptibility and longer term implantability. Such a potential prothesis would require no anti-coagulation regimen as do mechanical valves and would be more durable than bioprosthetic valves.